JP2024047490A - Desktop soldering device and soldering method using the same - Google Patents

Abstract

[Problem] To provide a benchtop soldering device that can be used continuously for long periods of time and a soldering method using the same. [Solution] In the benchtop soldering device, which is equipped with an elevation mechanism 4 that raises and lowers a holding frame 45 between a lower end position where a soldering through hole provided in a mask jig 51 supported by a holding frame 45 is immersed in molten solder jetted from the discharge port of a jet nozzle 2 that protrudes above a solder bath 1, and an upper end position where the mask jig 51 is upwardly spaced away from the jetted molten solder, the jet nozzle that forms the discharge port with a discharge tube portion 23 is raised and lowered by a portion of the discharge tube portion 23 including the upper edge. A notched jet nozzle 2A is formed by replacing the low point 230 with a bottom wall portion 232 that is notched, and a base portion 61 is fixed to the holding frame 45 or the mask jig 51, and at the lower end position, a standing plate portion 62 extending from the base portion 51 is provided with a shutter 6 that covers the low point 230, and at the upper end position, the standing plate portion 62 is separated above the bottom wall portion 232 so that the molten solder rising inside the discharge tube portion 23 flows out from the low point 230. [Selected Figure]

Description

The present invention relates to a small desktop soldering device and a soldering method using the same.

The applicant has proposed a soldering device capable of preheating for soldering electronic components, etc., to printed circuit boards.

Japanese Patent No. 5496968 JP 2021-22627 A

The tabletop soldering devices in Patent Documents 1 and 2 are tabletop devices that can not only preheat, but can also perform soldering in almost the same amount of time as before, even including preheating, and have been effective in improving productivity and reducing the cost of the device.

However, the desktop soldering devices in Patent Documents 1 and 2 were commercialized as small desktop devices suitable mainly for developing prototypes and small-lot production, and problems arose when the devices were used for long periods of time for mass production. Dross D and residual flux floated on the molten solder liquid surface M1 of the jet nozzle (see Figure 9A), causing variation in the soldering finish. When soldering is continued for long periods of time, measures are taken to clean and remove dross and the like floating on the surface of the molten solder every few hours, but this places a burden on the operator.

The present invention aims to solve the above problems by providing a tabletop soldering device and a soldering method using the same that can be used continuously for long periods of time while maintaining good soldering quality, without the burden on the operator of removing dross floating on the surface of the molten solder from the jet nozzle.

In order to achieve the above-mentioned object, a first aspect of the present invention is a bench-top soldering device equipped with a lifting mechanism for raising and lowering a holding frame between a lower end position where a soldering hole provided in a mask jig supported by a holding frame is immersed in molten solder jetted from the outlet of a jet nozzle protruding above a solder bath, and an upper end position where the mask jig is moved upwardly away from the jetted molten solder, wherein the jet nozzle forming the outlet in the outlet tube is a notched jet nozzle in which a part of the outlet tube is cut out, including the upper edge, to replace it with a bottom wall portion with a low area, and wherein the jet nozzle has a base fixed to the holding frame or the mask jig, and at the lower end position, a standing plate portion extending from the base is provided with a shutter that covers the low area, and at the upper end position, the standing plate portion is moved upwardly above the bottom wall portion so that the molten solder rising inside the outlet tube flows out from the low area.
A second aspect of the present invention is characterized in that, in the first aspect, the discharge port is rectangular in plan view, and a high wall portion having a high upper edge of the discharge tube portion and a low wall portion facing the high wall portion are provided on the long side of the rectangle. A third aspect of the present invention is characterized in that, in the second aspect, a middle wall portion having an upper edge height intermediate between the high wall portion and the low wall portion is provided on the short side of the rectangle connecting the high wall portion and the low wall portion. A fourth aspect of the present invention is characterized in that, in the first to third aspects, a plurality of discharge tube portions of the notched jet nozzle are provided, and the base is fixed to the holding frame or the mask jig at a location corresponding to the low point of each discharge tube portion, and a shutter is provided at the lower end position with the upright portion extending from the base to cover the low point. A fifth aspect of the present invention is characterized in that, in the fourth aspect, the plate surface of the upright portion of the shutter, the base of which is fixed to a retaining frame, extends upward with a bent portion at its lower end which bends gently from its lower end in a side view and protrudes outward, and as the upright portion descends from the upper end position to the lower end position, the bent portion guides the upright portion to the outside of the bottom wall portion, and the upright portion slides over the bottom wall portion and abuts against the bottom wall portion so as to block the low area.
In a sixth aspect of the present invention, in a tabletop soldering device having a lifting mechanism for lifting a holding frame between a lower end position where a soldering through hole provided in a mask jig supported by a holding frame is immersed in molten solder jetted from an outlet of a jet nozzle projecting above a solder bath, and an upper end position where the mask jig is upwardly spaced from the jetted molten solder, the jet nozzle forming the outlet with an outlet tube portion is a notched jet nozzle in which a part of the outlet tube portion including an upper edge is cut out and replaced with a bottom wall portion having a low portion, and a base portion is fixed to the holding frame or the mask jig, and at the lower end position, a standing plate portion extending from the base covers the low portion. The soldering method using a benchtop soldering device is characterized in that, using a benchtop soldering device equipped with a shutter, at the upper end position, the upright portion is separated above the bottom wall portion so that the molten solder rising inside the discharge tube portion flows out from the low place, and after the molten solder around the solder liquid level rising inside the notched jet nozzle toward the discharge port flows out from the low place, the shutter reaches the lower end position to block the low place, stopping the outflow of the molten solder from the low place, allowing the liquid level of the molten solder to rise toward the discharge port, and then the molten solder reaches the through hole to solder the component to be soldered. A seventh aspect of the present invention is characterized in that, in the sixth aspect, after the molten solder reaches the through hole and solders the component to be soldered, the shutter is moved away from the upper edge of the bottom wall portion toward the upper end position, and the molten solder between the upper edge and the solder liquid surface in the discharge tube portion flows over the upper edge and out of the discharge tube portion, and then the molten solder in the discharge tube portion is lowered.

The tabletop soldering device and the soldering method using the same of the present invention are tabletop devices that can be used continuously for long periods of time while maintaining good soldering quality, even without the operator having to remove impurities such as dross floating at the outlet of the jet nozzle, and are highly effective in maintaining quality and improving yields.

1 is a schematic side cross-sectional view of one embodiment of a desktop soldering device of the present invention. FIG. 2 is a cross-sectional view taken along line II-II of FIG. FIG. 2 is an enlarged plan view of the mask jig and its surroundings in FIG. 1 . FIG. 4 is an enlarged plan view of FIG. 3 after the mask jig has been removed. 3 is a cross-sectional view showing the holding frame of FIG. 2 at a lower end position. FIG. 2 is a perspective view of a notched jet nozzle. FIG. 3 is an enlarged view of the right end portion and its surroundings of the mask jig in FIG. 2 . FIG. 2 is an enlarged view of the vicinity of the notched jet nozzle of FIG. 1 . 1A to 1C are explanatory cross-sectional views showing how molten solder rises within a jet nozzle over time. 4(d) is an explanatory cross-sectional view showing the state in which the molten solder in the jet nozzle has reached the winding of the coil to be soldered, and FIG. 4(e) is an explanatory cross-sectional view showing the end of soldering between the winding and the terminal. FIG. 13 is an explanatory cross-sectional view of a circuit board and its surroundings with a through-hole immersed in molten solder, showing another embodiment in place of a coil. FIG. 12 is an explanatory cross-sectional view after the soldering in FIG. 11 is completed. FIG. 7 is a perspective view of a notched jet nozzle according to another embodiment, which is an alternative to that shown in FIG. 6.

The tabletop soldering device and the soldering method using the same according to the present invention will be described in detail below.
1 to 12 show one form of a desktop soldering device (hereinafter also simply referred to as the "soldering device") of the present invention, with FIG. 1 being a side cross-sectional view, FIG. 2 being a cross-sectional view taken along line II-II in FIG. 1, FIG. 3 being a plan view of the area around the mask jig in FIG. 1, FIG. 4 being a plan view of FIG. 3 excluding the mask jig in FIG. 3, FIG. 5 being a cross-sectional view of the holding frame in FIG. 2 at its lower end position, FIG. 6 being an oblique view of the notched jet nozzle, FIG. 7 being an enlarged view of the area around the mask jig in FIG. 2, FIG. 8 being an enlarged view of the area around the notched jet nozzle in FIG. 1, FIG. 9 being a cross-sectional view of molten solder rising inside the jet nozzle, FIG. 10 being a cross-sectional view of molten solder soldering a coil, FIGS. 11 and 12 being views of another embodiment replacing a coil, and FIG. 13 being an oblique view of another embodiment of a notched jet nozzle replacing FIG. 6. In order to make the drawings easier to understand, the essential parts of the invention are highlighted, some hatching is omitted in the cross-sectional views, and components and members that are not directly related to the present invention are omitted. The vertical cylinder and the bottomed cylinder of the solder bath in FIG.

(1) Benchtop Soldering Apparatus Benchtop soldering apparatus P includes a solder bath 1, a notched jet nozzle 2A, a heater HT, a pump 31, a lifting mechanism 4, and a shutter 6 (FIG. 1).
This tabletop soldering device P is provided with a solder bath 1 for circulating molten solder M by a pump 31, and a lifting mechanism 4 for raising and lowering the holding frame 45 between a lower end position where a soldering through hole 510 formed in a mask jig 51 supported by a holding frame 45 is immersed in the molten solder M jetted from an outlet 22 of a notched jet nozzle 2A protruding above the solder bath 1, and an upper end position where the mask jig 51 is separated upward from the jetting molten solder M. The lifting mechanism 4 raises and lowers the holding frame 45 between the lower end position in Fig. 5 where the soldering through hole 510 formed in the mask jig 51 is immersed, and the upper end position in Fig. 2 separated from the liquid level M1 of the jetting molten solder. The soldering target part of the work, which is the part to be soldered, is arranged on the through hole 510 at the upper end position, the soldering target part placed on the mask jig 51 is lowered to the lower end position and soldered, and after the soldering is completed, it is raised to the original upper end position.
In the side cross-sectional view of Figure 1, where an operator normally works while standing in front of the start switch S2, the left side of the paper is the front or front side, the right side of the paper is the rear or rear side, the top of the paper is the top, the front side of the paper is the right side, the back side of the paper is the left side, and the vertical direction of the paper including the lines running to the left and right of the paper is the horizontal direction.

The casing 9 is a box-shaped container that is rectangular in plan view as shown in Figs. 1 and 2. The solder tank 1 is disposed near the front vertical plate 91 of the horizontally arranged bottom plate 90, and a space is secured between the solder tank 1 and the rear vertical plate 92, which is divided by a partition wall (not shown), and the motor 32 for driving the pump 31 is disposed in the space. The front vertical plate 91, rear vertical plate 92, and both side vertical plates 93 and 94 surround the periphery of the bottom plate 90 to accommodate the solder tank 1, motor 32, etc. The rear vertical plate 92 is made high, and its upper edge is bent to extend forward to form the upper plate 95, which further slopes downward to cover the motor 32. A pump cover that covers the upper part of the pump 31 is provided from the upper plate 95. Meanwhile, the upper part of the front vertical plate 91 slopes backward to form an inclined plate portion, and a horizontal flange extends backward from the upper edge of the inclined plate portion. The space between the horizontal flange of the front upright plate 91 and the pump cover is an upper opening, in which the jet nozzle 2 of the solder bath 1 is located.

The solder tank 1 is a container that contains molten solder M heated by a heater HT within a casing 9 (Fig. 1). It has a tank body that stores the molten solder M, and further has a horizontally elongated cylinder portion 15 and a vertical cylinder portion 16 so that the molten solder M within the tank body is circulated by a pump 31 and the circulating molten solder M is jetted from a discharge port 22. The tank body is a rectangular box container that is open on the top and is made up of a plate-shaped bottom portion 10, a front wall portion 11, a rear wall portion 12, and both side walls 13.
1 and 2, the oblong cylinder 15 is a rectangular cylinder with a lid and a bottom, and the lower end of a hanging plate 19 suspended from the upper edges of the front wall 11 and rear wall 12 is fixed to the lid and bottom of the oblong cylinder 15, and the oblong cylinder 15 is placed horizontally in the solder bath 1. A circular discharge side port 15b is provided on the upper surface of the oblong cylinder 15 near the lid, which corresponds to the front, and a suction side port 15a is provided on the lower surface of the oblong cylinder 15 near the bottom, which corresponds to the rear. A hole for a pump 31 is formed on the upper surface of the oblong cylinder 15 above the suction side port 15a.
The vertical cylinder portion 16 is a rectangular cylinder with a bottomed cylinder body 17 that has a circular cross section and is slightly smaller in size than the rectangular cylinder body 16. The bottomed cylinder body 17 is inserted into the horizontally elongated cylinder portion 15 from the discharge side opening 15b as shown in Figure 2, so that the vertical cylinder portion 16 stands upright on the horizontally elongated cylinder portion 15. A guide hole 17a is provided on the cylindrical side of the bottomed cylinder body 17 to connect the inside of the horizontally elongated cylinder portion 15 and the inside of the vertical cylinder portion 16.

The notched jet nozzle 2A is a jet nozzle 2 with a low point 230 in which a part of the discharge tube part 23 forming the discharge port 22 in a conventional jet nozzle 2, in which the upper edge height of the discharge tube part 23 was the same, has been replaced with a flat low wall part 232 in which the upper edge 23a is notched to form the low point 230 (Figs. 1 and 6).

In this embodiment, the jet nozzle 2 is an integrated unit of a cylindrical base end 21 with a lid, a discharge tube portion 23 that surrounds an opening on the top lid of the base end 21, spreads out like a fan upward as shown in Fig. 2, and extends vertically upward while keeping its width constant. The base end 21 is a rectangular tube, while the discharge tube portion 23 spreads out widely in the left-right direction of the device toward the discharge port 22 at the tip, making the discharge port 22 a horizontally elongated rectangle (Fig. 4). The discharge port 22 is long in the left-right direction, so that multiple workpieces (here, motor coils 55, hereinafter simply referred to as "coils") can be set on the mask jig 51 at one time.
2, the opening width of the upper discharge port 22 of the discharge tube portion 23 is wider in a trumpet shape than the opening width of the square base end portion 21 fitted into the vertical tube portion 16, but the area around the discharge port 22 is a short tube portion that is rectangular in a plan view. On the other hand, in the plan view of FIG. 4, the discharge tube portion 23 protrudes upward only from the central area in the front-to-rear direction of the upper plate portion 211 of the base end portion 21. The jet nozzle 2 is attached to the upper end portion of the vertical tube portion 16 by fitting the base end portion 21, which serves as the lower side connecting portion, and the discharge tube portion 23 is provided so that it is connected to the vertical tube portion 16 and the horizontally elongated tube portion 15 and has the discharge port 22 protruding above the solder bath 1.

Furthermore, in the conventional jet nozzle 2 in which the upper edge 231a of the high wall portion 231 corresponding to the long side of the rectangle in plan view is the same height in the discharge tube portion 23 forming the discharge port 22 of this jet nozzle 2, the conventional high wall portion 231 located on the front side is replaced with a flat plate-like low wall portion 232 having a low place 230 by cutting out the upper edge of the high wall portion 231 (FIG. 6). On the long side of the rectangular discharge port 22, the high wall portion 231 with a high upper edge of the discharge tube portion 23 and the low wall portion 232 on the wall portion facing the high wall portion 231 are provided. In the conventional jet nozzle, the front side wall portion of the discharge tube portion 23 around the discharge port 22 is changed to the low wall portion 232 with the low place 230 formed by partially removing the wall portion extending downward including the upper edge of the high wall portion.
Specifically, the front low wall portion 232 is lowered by one step compared to the rear high wall portion 231 as shown in Fig. 6. When soldering, the molten solder M rises up the jet nozzle, and the solder liquid level M1 that reaches the discharge port 22 is not used for soldering as it is, but the molten solder M, including dross D floating on the solder liquid level M1, is first made to flow out of the discharge tube portion 23 from the lowered low point 230 of the lowered low wall portion 232 as shown by the white arrow in Fig. 6 by utilizing the molten solder M that is jetted from the discharge port 22 and rises inside the discharge tube portion 23. After that, the molten solder M with a clean liquid level is used for soldering. The molten solder M2, dross D, etc. that flow out and are dropped as shown in Fig. 9(b) are received by the overflow receiver 18 and returned to the solder bath 1.
Incidentally, on both the left and right sides of the low wall portion 232, side wall margins 2321 are left with a small width while maintaining the height of the high wall portion 231. This is to reinforce the strength around the discharge port 22, and also to ensure that the low point 230 is closed reliably by the surface contact between the side wall margins 2321 and the shutter 6 at the lower end position of the holding frame 45 (described in detail later).

Further, the discharge port 22 is a discharge tube portion 23 having a rectangular shape in plan view, and in addition to the long side of the rectangle being made into a high wall portion 231 and a low wall portion 232, here, a middle wall portion 233 whose upper edge height is intermediate between the high wall portion 231 and the low wall portion 232 is provided on the short side of the rectangle connecting the high wall portion 231 and the low wall portion 232 (FIG. 6). The middle wall portion 233 is also made one step lower than the high wall portion 231 on the rear side, but its upper edge 233a is set higher than the low wall portion upper edge 232a that forms the low place 230. The specific drop width from the high wall portion upper edge 231a to the middle wall portion upper edge 233a is smaller at 0.5 mm to 2 mm than the drop width from the high wall portion upper edge 231a to the low wall portion upper edge 232a, which is 5 mm to 20 mm.
Incidentally, the reason for providing the middle wall portion 233 which is one step lower than the high wall portion 231 is that the molten solder M jetting out of the discharge port 22 passes through the through hole 510 and is pumped to supply an amount exceeding the amount of molten solder used for soldering so as to prevent a shortage of solder, thereby allowing the excess molten solder M to flow over the upper edge 233a of the middle wall portion and out of the discharge tube portion 23 as indicated by the black arrow in FIG. 6.

The heater HT is a heat source for heating the molten solder M in the solder bath 1 to keep it molten. Here, two heaters HT are disposed in the solder bath 1 near the bottom 10 in the direction perpendicular to the paper surface as shown in FIG.
The pump 31 circulates the molten solder M in the solder tank 1, and in this embodiment, the pump 31 is installed near the rear wall 12 in the solder tank 1, and the motor 32 that drives the pump 31 is installed outside the solder tank 1, near the rear upright plate 92 in the casing 9. A belt 35 is wound around a pulley 34 fixed to the motor 32 and a pulley 33 fixed to the pump 31, and the rotation of the motor 32 rotates the impeller 31a of the pump 31 disposed in the horizontally elongated cylindrical portion 15, causing the molten solder M to jet from the discharge port 22 of the notched jet nozzle.

In this manner, the shaft of the pump 31 is inserted into the pump hole 15c, and the impeller 31a attached to the tip of the shaft is disposed within the horizontally elongated cylindrical portion 15. When the pump 31 is operated, the molten solder M sucked in from the suction side port 15a passes through the horizontally elongated cylindrical portion 15 and the vertical cylindrical portion 16 as indicated by the black arrow in FIG. 1, and rises within the discharge cylindrical portion 23 of the notched jet nozzle 2A, and is jetted out from the discharge port 22.
However, up until now, soldering has been performed as is with the molten solder M including the rising solder liquid surface M1, but even if the molten solder M rising inside the discharge tube portion 23 is made into a jet state at the discharge port 22, impurities such as dross D floating on the liquid surface M1 may remain.
Therefore, in the present invention, impurities such as dross D floating on the liquid surface M1 and a portion of the molten solder M including the liquid surface are allowed to flow down from the lower part 230 of the bottom wall part 232, and the cleaned molten solder M on the liquid surface M1 is used for soldering the workpiece. Soldering is performed below the lower end position of the holding frame 45. Then, the molten solder M in excess of the amount required during soldering is allowed to flow down over the middle wall part 233 and out of the discharge tube part 23.

The lifting mechanism 4 comprises a cylinder 41 as an actuator and a holding frame 45. The cylinders 41, which are air cylinders, are provided near both side walls 13, 14 inside the casing 9. Both cylinders 41 stand upright, and a horizontally disposed holding frame 45 is fixed to the tip of a rod 42 extending upward from the cylinder body, forming the lifting mechanism 4 that lifts and lowers the holding frame 45 (Figs. 2 and 5). The holding frame 45, which has an outer shape slightly smaller than that of the top opening, moves up and down above the top opening created by the casing 9 (Figs. 1 and 2).
When the pump 31 is in operation and the rod 42 of the lifting mechanism 4 retracts, the holding frame 45 and the shutter 6, which will be described in detail later, reach their lower end positions and stop, and the soldering through hole 510 provided in the mask jig 51 is immersed in the molten solder M jetting from the discharge port 22. When the molten solder M jets from the discharge port 22, the solder liquid level M1 rises in the through hole 510, soldering the terminal 552 and the winding 551 of the coil 55 associated with the workpiece set at the upper opening of the through hole 510. On the other hand, when the rod 42 advances, the mask jig 51 moves upward away from the molten solder M jetting from the discharge port 22, and the holding frame 45 and the mask jig 51 reach their upper end positions and stop.

The shutter 6 is a shielding member in which a base 61 is fixed to the mask jig 51 or the holding frame 45, and a standing plate portion 62 having a flat plate surface extending upward from the base 61 is abutted against the outer surface of the low wall portion 232 at the lower end position so as to block the low place 230 on the plate surface side, thereby stopping the outflow of the molten solder M from the low place 230. When the holding frame 45 reaches the lower end position, the shutter 6 which fixes and integrates the base 61 to the holding frame 45 also reaches the lower end position, and the shutter 6 stops the molten solder M that has reached the discharge port 22 and flowed out from the low place 230. Here, "stopping the molten solder M flowing out from the low place 230" does not necessarily mean stopping it completely, but is considered to stop it if the amount of the flowing out can be reduced and the liquid level M1 of the molten solder can be raised to the discharge port 22.
On the other hand, once soldering is completed, the shutter 6 together with the holding frame 45 moves away from the upper end position of the initial state, which is above the upper edge 232a of the bottom wall portion 232, allowing the molten solder M to flow out of the discharge tube portion 23 from the low point 230 in preparation for the next soldering.

The shutter 6 of this embodiment is an L-shaped member in side view, and the base 61 of the horizontal part is fixed to the lower side holding frame 45 by fasteners 69 across the frame opening 450 of the holding frame 45 (FIG. 4). A recess 515 having a depth corresponding to the height of the low part 230 is provided on the lower surface 51b side of the mask jig 51 in a region corresponding to the bottom wall part 232 as shown in FIG. 5. The tip horizontal edge of the low plate part 62L of the approximately square standing plate part 62 extending upward in an L-shape in side view from the base 61 abuts or is close to the lower surface 51b of the mask jig 51 attached to the holding frame 45, and in the region of the recess 515, a high plate part 62H which is one step higher than the standing plate part 62 abuts or is close to the bottom surface of the recess 515 (FIG. 7).
Furthermore, the plate surface of the standing plate portion 62 of the shutter 6, whose base portion 61 is fixed to the holding frame 45, has a bent portion 621 at its lower end portion that bends gently from the lower end of the plate surface in a side view and projects outward, and extends upward (FIG. 8). When the shutter 6 descends from the upper end position to the lower end position, the bent portion 621 guides the standing plate portion 62 to the outside of the bottom wall portion 232, so that the standing plate portion 62 can smoothly slide on the bottom wall portion 232 and the side wall margin 2321 and come into contact with the low wall portion 232 so as to block the low place 230.
In order to make the shutter 6 function, the mask jig 51 is attached to the holding frame 45 via the spacer 7 (FIGS. 2 and 3), but instead of this, the holding frame 45 may be integrated with the spacer 7, or the mask jig 51 may be integrated with the spacer 7. Also, the base 61 is attached to the holding frame 45, and the shutter 6 has the standing plate portion 62 whose tip faces upward from the base 61. However, the base 61 may be attached to the lower surface 51b of the mask jig 51, and the shutter 6 has the standing plate portion 62 whose tip faces downward. In such a case, it is more preferable that the tip portion of the flat downward standing plate portion 62 has a bent portion that is bent outward from the facing bottom wall portion 232 in a J-shape when viewed from the side.

In addition, in this soldering device P, the molten solder M, whose liquid level is rising due to the pump 31, is jetted out of the discharge port 22, but the molten solder M, including dross D floating on the solder liquid level M1, is first poured out of the discharge tube portion 23, and then the holding frame 45 of the lifting mechanism 4, which is the next step, reaches the bottom end position and closes the low point 230 with the shutter 6. Thereafter, the liquid level M1 of the molten solder M rises above the upper edge 232a of the bottom wall portion, reaches the through hole 510 of the mask jig 51, and is immersed for the time required for soldering, after which the shutter 6 for the next step moves up, and then the controller, which is a control means, stops the pump 31.
Specifically, the pump 31 and the lifting mechanism 4 are started by turning on the start switch, and the molten solder M, whose liquid level is rising due to the pump 31, moves toward the discharge port 22. Regardless of whether or not the molten solder M contains dross D or the like floating on the solder liquid level M1, the first part of the molten solder M, whose liquid level is rising inside the discharge tube 23, flows down from the low point 230, and then the holding frame 45 reaches the lower end position. Then, the liquid level M1 of the molten solder after flowing down rises inside the discharge tube 23 blocked by the shutter 6, soaks the through hole 510 of the mask jig 51, and soldering is performed for a required time with the molten solder M containing the clean solder liquid level M1 from which the dross D or the like has been removed. After that, when the soldering is completed and the holding frame 45 rises, impurities such as dross D newly generated during soldering may float on the solder liquid level M1. Therefore, the shutter 6 rises away from the upper edge 232a of the bottom wall portion first, and after a short time for the dross D and the like to flow out from the low place 230 where the shutter 6 is open, the pump 31 is stopped and the solder liquid level M1 drops inside the notched jet nozzle 2A. A sequence control is adopted in which each step of the control is carried out in sequence according to these predetermined procedures.

As described above, the present invention provides a soldering apparatus P that includes the notched jet nozzle 2A and shutter 6 of the above configuration, and efficiently removes impurities such as dross D from the molten solder M at the soldering point, thereby providing the desired soldering apparatus P that is capable of continuous soldering operation.
Furthermore, the present invention can also be applied to another type of notched jet nozzle 2A in which a plurality of (here, two) discharge tube parts 23 are erected from the base end part 21 as shown in FIG. 13. In such a case, a plurality of discharge tube parts 23 of the notched jet nozzle 2A protruding above the solder bath 1 are provided, and a base part 61 is fixed to the holding frame 45 or mask jig 51 at a location corresponding to the low point 230 of each discharge tube part 23, and a shutter 6 is provided at the lower end position, in which a standing plate part 62 extending from the base part 61 closes the low point 230. At the upper end position, each standing plate part 62 is spaced above each low wall part 232, allowing the molten solder M rising inside the discharge tube part 23 to flow out from each low point 230. Compared to the one notched jet nozzle shown in FIG. 8 of this embodiment, the productivity of soldering can be significantly increased.

(2) Soldering Method Using a Desktop Soldering Apparatus Next, one soldering method using the soldering apparatus P and its operation will be described.
As described above, the soldering device P is provided with a solder tank 1 that contains molten solder M heated by a heater HT in the tank, and the molten solder M is circulated by a pump 31. When the molten solder M passes the bottom wall portion 232 of the discharge port 22, a notched jet nozzle 2A having a low point 230 that causes the molten solder M to flow down outside the discharge tube portion 23 protrudes above the solder tank 1. The device is also provided with a shutter 6 that closes the low point 230 of the bottom wall portion 232, and the shutter 6 closes the low point 230 to jet the molten solder M from the discharge port 22. The device is also provided with an elevation mechanism 4 that raises and lowers the holding frame 45 between a lower end position where the through hole 510 of a mask jig 51 supported by a holding frame 45 is immersed in the jetting molten solder M to solder the workpiece, and an upper end position where the mask jig 51 and the shutter 6 are separated from the jetting molten solder M.

In this soldering method, the power switch S1 is turned on in advance, and the molten solder M is stored in the solder bath 1 by the heater HT, as shown in the initial state of FIG.
1 is set in a mask jig 51, and flux is applied to the portion of the workpiece to be soldered. As shown in Fig. 9(c), the portion to be soldered, in which a winding 551 is wound around a terminal 552 of the coil 55 that will be the soldered component, is set in a through hole 510 of the mask jig 51. In the present invention, the mask jig 51 around the through hole 510 forms a recess 512, and the recess 512 is also considered to be included in the through hole 510. The winding 551 to be soldered is a coated copper wire.
Specifically, the mask jig 51 on which the object to be soldered is set is placed on the top opening of a flux applicator (not shown) (Patent No. 5421955) and flux is applied. Flux is applied to the soldering target portion using the applicator. Next, the mask jig 51 on which the coil 55, which has been flux-coated, is set by a robot on the holding frame 45 to the state shown in FIG. 2.

Thereafter, the operator presses the start switch S2, and the control means, the lifting mechanism 4, etc. are used to perform a timed operation to solder the terminal 552 of the coil 55 to the winding 551 wound around the terminal 552. The operation steps and effects are described below.
First, the start switch S2 is turned on to start the pump 31 and the lifting mechanism 4. When the pump 31 is started, the molten solder M rises in the notched jet nozzle 2A from the state shown in FIG. 2 as indicated by the white arrow in FIG. 1. Since the molten solder M rises in the jet up method, the air between the mask jig 51 and the liquid surface M1 of the molten solder is effectively expelled. The liquid surface M1 of the molten solder that has arrived at the discharge port 22 may contain floating impurities such as dross D as shown in FIG. 9(A). If this solder liquid surface M1 is guided to the soldering location, there is a high probability of soldering failure. Therefore, the molten solder M around the solder liquid surface M1 that rises in the notched jet nozzle 2A toward the discharge port 22 is made to flow out from the low point 230. After that, the shutter 6 reaches the lower end position and closes the low point 230. The outflow of the molten solder M from the low point 230 is stopped, and the liquid level M1 of the molten solder is set to rise again toward the discharge port 22. Thereafter, the molten solder M reaches the through hole 510 and solders the component to be soldered.
In the present invention, when the molten solder M rising inside the discharge tube portion 23 indicated by the black arrow in Figure 9 (a) reaches the upper edge 232a of the bottom wall portion, time is taken for the dross D and the molten solder M that floats it to flow down from the low point 230 to the outside of the discharge tube portion 23 as shown in Figure 9 (b), and the solder liquid level M1 is changed to a normal state free of dross D and the like.

After the solder liquid level M1 is changed to the normal state, the rod 42 retracts, causing the holding frame 45 and the mask jig 51 to descend, and then the shutter 6 fixed to the holding frame 45 blocks the low point 230, stopping the outflow of the molten solder M from the low point 230. The shutter 6 comes into surface contact with the side wall margins 2321 of the low wall portions 232 on both sides of the low point 230, blocking the low point 230. The surface contact increases the frictional resistance passing between the shutter 6 and the side wall margins 2321, suppressing the leakage of the molten solder M. By stopping the outflow of the molten solder M from the low point 230, the molten solder M can rise to a position higher than the low wall portion 232 as shown in FIG. 9C, and the liquid level M1 of the molten solder rises to a height exceeding the low wall portion 232, and further enters the through hole 510, whereby the solder liquid level M1 approaches the upper opening of the through hole 510.
Here, preheating is performed while the mask jig 51 is lowered, the shutter 6 covers the low point 230, the molten solder M rises after the cover is closed, and the solder liquid surface M1 approaches the upper opening of the through hole 510. The flux is activated and the workpiece is heated, which improves the soldering process by mitigating the thermal shock of soldering.

Next, the molten solder M, whose solder liquid level M1 has reached the upper opening of the through hole 510, burns the enamel coating on the winding 551 set at the upper opening of the through hole 510 with its heat, and then solders the winding 551 to the terminal 552 of the coil 55 (FIG. 10(d)). When soldering is completed, the rod 42 extends first, and the mask jig 51 and the shutter 6 rise to the upper end position as shown by the white arrow in FIG. 10(c). A little later, the pump 31 stops, and the solder liquid level M1 drops as shown by the black arrow in the same figure. As the shutter 6, which had been shielding the low point 230, rises first, dross D, flux, etc. floating on the solder liquid level M1 that appeared during soldering are allowed to flow down from the low point 230 to the outside of the notched jet nozzle together with the molten solder M that was above the upper edge 232a of the bottom wall portion.
When the molten solder M reaches the through hole 510, the soldering of the component to be soldered is completed. After soldering, the shutter 6 is moved away from the upper edge 232a of the bottom wall portion 232 toward the upper end position, and the molten solder M between the upper edge 232a and the solder liquid surface M1 in the discharge tube portion 23 flows beyond the upper edge 232a and out of the discharge tube portion 23, and then the molten solder M in the discharge tube portion 23 is lowered. The symbol F in Fig. 10(e) indicates hardened solder after soldering.
When the holding frame 45, mask jig 51, and shutter 6 reach their upper end positions due to the extension of the rod 42, the signal to the lifting mechanism 4 is turned off, the series of soldering steps ends, and the coil 55 that has been soldered is removed by the robot. Also, by stopping the pump 31, the liquid surface M1 of the molten solder returns to the initial state shown in FIG.

In the case of continuous operation, the above-mentioned series of soldering steps are repeated. Even if the series of soldering steps are repeated, as shown in Fig. 9(b), just before soldering to the soldering target portion, impurities such as dross D floating on the solder liquid level M1 flow out from the low point 230, and soldering is performed while maintaining a clean solder liquid level M1, and even after soldering is completed, dross D and flux stains generated during soldering are expelled from the low point 230 to the outside of the notched jet nozzle 2A, and the molten solder M descends to prepare for the next soldering.
Since the liquid surface M1 of the molten solder in the notched jet nozzle 2A is continuously maintained in a clean state for the subsequent soldering, this is a desired soldering method that allows continuous operation while maintaining good soldering quality.

9 and 10 are schematic diagrams, and the soldering target portion, where the coil 55 is wound around the terminal 552, is shown at a position higher than the through hole 510, but in reality, the soldering target portion is set in a state in which it contacts the upper opening of the through hole 510.
11 and 12 are views of another embodiment replacing Fig. 9 and Fig. 10, in which an electronic component 53 mounted on a board 52 is used as a workpiece. At the lower end position where a through hole 510 provided in a mask jig 51 is immersed, a through hole 520 into which a lead 531 of the electronic component 53 is inserted is also immersed, and soldering is performed. When the pump 31 stops and the solder liquid level M1 drops, the lead 531 of the electronic component 53 exposed on the board lower surface 52b side is soldered as desired, resulting in the mounted board product shown in Fig. 12. The lead 531 and the solder blend together to form a good fillet F. Reference numeral 54 denotes a container case.

(3) Effects The tabletop soldering device and the soldering method using the same thus constructed are small tabletop type devices, yet can maintain good soldering quality and can be used continuously for long periods of time.
As soldering continues, dross D, which is an oxide of solder, is generated and accumulates, but even if impurities such as dross D, flux, and even enamel residue float on the solder liquid surface M1, when new soldering is performed, the liquid surface M1 of the molten solder used for soldering is made clean before soldering, so that no soldering defects occur.

This soldering device P is equipped with a notched jet nozzle 2A, a shutter 6, and a lifting mechanism 4, and when the standing plate portion 62 is above the upper edge of the bottom wall portion 232 at the upper end position, it allows the molten solder M to flow over the bottom wall portion 232. Therefore, even if impurities such as dross D float on the liquid surface M1 of the molten solder that has risen inside the notched jet nozzle 2A during soldering, the impurities are discharged from the low point 230 to the outside of the notched jet nozzle 2A together with the molten solder M around the liquid surface M1 that floats the impurities. Since the low wall portion 232 is provided on the front side of the discharge tube portion 23, the operator can easily visually confirm that the dross D and the like are being discharged smoothly. After that, the holding frame 45 moves to the lower end position by the action of the lifting mechanism 4, and the low point 230 is closed by the shutter 6. By blocking the low point 230, the liquid surface M1 of the clean molten solder after discharge rises over the upper edge 232a of the bottom wall portion and passes through the through hole 510, allowing the soldering target portion of the work set on the mask jig 51 to be satisfactorily soldered with the molten solder M free from dross D, etc.
In the discharge tube portion 23 of the notched jet nozzle 2A, normal molten solder M is prepared after the molten solder M containing impurities is discharged, and this is used for soldering as it is, so that no soldering defects occur.

In addition, the soldering process repeats the steps from FIG. 9(a) to FIG. 10(e) each time a soldering run is completed, so the liquid surface of the new molten solder M that rises to the discharge port 22 for a new soldering run is removed by flowing out of the discharge tube portion 23 from the low point 230, regardless of whether dross D or the like is floating on the liquid surface M1 as in FIG. 9(b). Therefore, the molten solder M in FIG. 10 used for soldering is always normal, and soldered products of guaranteed quality can be produced even when soldering is performed continuously for a long period of time.

In addition, when soldering is completed and the shutter 6 that was blocking the low point 230 is raised, a control means is employed that moves the shutter 6 away from the upper edge 232a of the low wall portion while the solder liquid level M1 after soldering is at a position higher than the upper edge 232a of the low wall portion. This allows floating impurities such as dross D and flux that are generated during soldering to be quickly discharged from the low point 230.

Furthermore, the discharge of the molten solder M containing dross D and the like from the low place 230 to the outside of the notched jet nozzle 2A during the process in which the first solder liquid level M1 rises in the discharge tube 23, and the discharge of the molten solder M containing dross D and the like from the low place 230 to the outside of the discharge tube 23 during the process in which the second solder liquid level M1 descends inside the discharge tube 23 after soldering is completed, can be performed only by the lifting mechanism 4 and the control means, making this an extremely excellent invention. The first discharge makes good use of the force of the pump 31 to raise the molten solder M, and the second discharge makes use of potential energy, so that no new power source is required to remove impurities such as dross D.
In the first operation process in which the soldering device P itself solders the molten solder M toward the discharge port 22 without the intervention of a human hand such as an operator, and in the second operation process in which the molten solder M descends inside the discharge tube 23 to the initial state shown in FIG. 2 after soldering is completed, the solder liquid surface M1 inside the discharge tube 23 can be returned to a clean state, which is extremely beneficial. This makes it possible to continue producing soldered products of stable quality for a long period of time, contributing to improved productivity. Until now, workers have had to remove dross D and the like floating on the discharge port 22 every hour, but now it is sufficient to simply remove impurities such as dross D that have flowed down into the solder bath 1 at the end of work for the day. This not only improves productivity, but also greatly contributes to reducing the workload.

Furthermore, if multiple discharge tubes 23 of the notched jet nozzle 2A protruding above the solder bath 1 are provided, and a shutter 6 is provided at the location corresponding to the lower part of each discharge tube 23, the number of discharge ports 22 will increase accordingly, so that one discharge tube 23 can solder multiple times the number of soldered parts, thereby significantly increasing productivity. As mentioned above, the soldering device P itself can autonomously remove the dross D on the solder liquid surface M1 of the discharge port 22 used for soldering without human assistance, leading to labor savings. Furthermore, since this tabletop soldering device P is compact, if multiple units are lined up, mass production can be automated without taking up much installation space.

In addition, if the discharge port 22 is rectangular in plan view and a middle wall portion 233 is provided on the short side of the rectangle connecting the high wall portion 231 and the low wall portion 232, with the upper edge height being halfway between the high wall portion 231 and the low wall portion 232, molten solder M exceeding the amount required for soldering during soldering can be discharged from the upper edge 233a of the middle wall portion to the outside of the discharge tube portion 23. The middle wall portion 233 creates an escape route for the molten solder M that is jetted out. If the amount of soldering is insufficient, soldering defects will occur, but it is difficult to supply only the amount required for soldering. By providing the middle wall portion 233, it is possible to provide a range in the amount of molten solder M supplied to the through hole 510 by the pump 31, making it easier to operate the soldering device P and enabling stable production of soldered products.

In addition, if the plate surface of the standing plate portion 62 has a bent portion 621 at its lower end portion that bends from its lower end in a side view and projects outward, and the bent portion 621 guides the standing plate portion 62 to the outside of the low wall portion 232 when descending from the upper end position to the lower end position, and the standing plate portion 62 slides along the low wall portion 232 and abuts against the low wall portion 232 so as to block the low place 230, then even if the lifting mechanism 4 is repeatedly raised and lowered, the standing plate portion 62 will not hit the upper edge 232a of the low wall portion when descending from the upper end position to the lower end position, causing a breakdown. The guide of the bent portion 621 allows the standing plate portion 62 to reliably block the low place 230.
In this way, the present tabletop soldering device and the soldering method using the same exhibit the many excellent effects described above and are extremely effective.

The present invention is not limited to the above embodiment, and can be modified within the scope of the present invention according to the purpose and application. The shape, size, number, materials, and composition of the solder bath 1, notched jet nozzle 2A, discharge tube 23, pump 31, lifting mechanism 4, mask jig 51, shutter 6, etc. can be appropriately selected according to the application.

REFERENCE SIGNS LIST 1 Solder bath 2A Notched jet nozzle 22 Discharge port 23 Discharge tube portion 230 Low portion 231 High wall portion 232 Low wall portion 4 Lifting mechanism 45 Holding frame 51 Mask jig 510 Through hole 53 Electronic component (workpiece, component to be soldered)
55 Coil (workpiece, soldered part)
6: shutter; 61: base; 62: upright portion; M: molten solder; M1: solder liquid level (liquid level)
P Desktop soldering device (soldering device)

Claims (7)

A benchtop soldering device having a lifting mechanism for lifting a holding frame between a lower end position where a soldering through hole provided in a mask jig supported by a holding frame is immersed in molten solder jetted from an outlet of a jet nozzle protruding above a solder bath, and an upper end position where the mask jig is upwardly separated from the jetted molten solder,
The jet nozzle in which the discharge port is formed by a discharge tube portion is replaced with a bottom wall portion having a low portion by cutting out a part of the discharge tube portion including an upper edge, to form a notched jet nozzle,
A base is fixed to the holding frame or the mask jig, and a shutter is provided at the lower end position, the shutter having an upright portion extending from the base to cover the low portion;
a bottom wall portion that is spaced apart from the bottom wall portion at the upper end position, so that molten solder rising inside the discharge tube portion flows out from the lower portion. The tabletop soldering device according to claim 1, in which the discharge port is rectangular in plan view, and a high wall portion with a high upper edge of the discharge tube portion and the low wall portion are provided on the opposing wall portion of the high wall portion on the long side of the rectangle. The tabletop soldering device according to claim 2, wherein a middle wall portion is provided on the short side of the rectangle connecting the high wall portion and the low wall portion, the upper edge of which is intermediate between the high wall portion and the low wall portion. The benchtop soldering device according to any one of claims 1 to 3, in which a plurality of discharge tube parts of the notched jet nozzle are provided, and the base part is fixed to the holding frame or the mask jig at a location corresponding to the low point of each discharge tube part, and a shutter is provided at the lower end position, in which the upright part extending from the base part covers the low point. The tabletop soldering device according to claim 4, wherein the plate surface of the upright portion of the shutter, the base of which is fixed to the holding frame, extends upward with a bent portion at the lower end that bends gently from its lower end in a side view and protrudes outward, and when the upright portion descends from the upper end position to the lower end position, the bent portion guides the upright portion to the outside of the low wall portion, and the upright portion slides over the low wall portion and abuts against the low wall portion so as to block the low area. a desktop soldering device having a lifting mechanism for lifting and lowering a holding frame between a lower end position where a soldering through hole provided in a mask jig supported by a holding frame is immersed in molten solder jetted from a discharge port of a jet nozzle projecting above a solder bath, and an upper end position where the mask jig is separated upward from the jetted molten solder, the desktop soldering device being used in which the jet nozzle forming the discharge port at the discharge tube portion is a notched jet nozzle in which a part of the discharge tube portion including the upper edge is cut out and replaced with a bottom wall portion having a low portion, the desktop soldering device having a base fixed to the holding frame or the mask jig, a standing plate portion extending from the base at the lower end position is provided with a shutter that closes the low portion, and the standing plate portion is separated above the bottom wall portion at the upper end position so that the molten solder rising inside the discharge tube portion flows out from the low portion,
A soldering method using a benchtop soldering device, characterized in that after the molten solder around the solder liquid level rising inside the notched jet nozzle toward the outlet flows out from the low point, the shutter reaches a lower end position to block the low point, stopping the outflow of molten solder from the low point and allowing the liquid level of the molten solder to rise toward the outlet, and then the molten solder reaches the through hole to solder the component to be soldered. A soldering method using a tabletop soldering device according to claim 5, in which, after the molten solder reaches the through hole and solders the component to be soldered, the shutter is moved away from the upper edge of the bottom wall portion toward the upper end position, and the molten solder between the upper edge and the solder liquid surface in the discharge tube portion flows out of the discharge tube portion beyond the upper edge, and then the molten solder in the discharge tube portion is lowered.

Images